Washer Supply Pipe Size Question

Hi all, I am moving my washer and want to run PEX for supply. The washer will be about 15 feet from a main supply line, which is 3/4 inch CPVC. I was going to use 1/2 inch PEX for the washer....is this reasonable?

Also I have never attempted to tie into a hot water line, I will turn off valve leading to hot water tank, but there is no valve on the line coming out of the tank. Is this a problem?

The thing to consider about pipe size, no matter what the medium, is the amount of flow. The smaller the pipe, the longer it will take for the machine to fill. Keep in mind that the gold standard for pipe size is copper. CPVC and PEX both have a smaller inside diameter than copper of the same size, 3/4" of these materials are about the same a 1/2" copper, so I think you might want to run 3/4" PEX rather than the 1/2". When you turn off the cold water supply to the water heater, no more hot water will enter the supply system. There will be some water left in the pipes but will drain if you open the pipe at the low end and the top end of the system. Using CPVC you would want the pipe ends dry where you make you joints, I don't think that's as critical with PEX.

1/2" is fine for a washer. That is fine for PEX, CPVC, Copper and galvanized.

Normally you have a main cold water shutoff for a home, and the cold feed shutoff for the water heater in a home.
Other fixtures may have individual shutoffs with perhaps the showers and the tubs not having that provision.

I have 1/2" PEX run for my washing machine supplies & have no complaints.

As Terry said, turning off the valve at the water heater will turn off the water to the hot supply except for any water remaining in the line above the point you intend to tie in. One word of caution though. If you are not home alone when doing the work, I suggest you shut off the main to the house. While doing some similar work recently, my wife turned on a faucet and did not turn it all the way to cold. As a result I received a nice shower when the cold water crossed over to the hot water side at the faucet!

While doing some similar work recently, my wife turned on a faucet and did not turn it all the way to cold. As a result I received a nice shower when the cold water crossed over to the hot water side at the faucet!

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Jamie and I were replacing a water heater yesterday, and one of the people in the home insisted on taking a shower while we had the water heater disconnected. It was like working under a waterfall.
Wood floors too. Not much we could do about it.